The US Department of State released a report on Friday which concluded that Chinese maritime maps that claim almost all islands and waters to its south don't comply with the international law of the sea. The 26-page Limits in the Seas study, prepared by Bureau of Oceans and International Environmental and Scientific Affairs, considered the maps, particularly the “nine-dashed line” map of that swallowed almost all of the South China Sea, which Vietnam calls the East Sea.

In May 2009, the Chinese government sent two diplomatic notes to the UN Secretary General that asserted indisputable sovereignty over the islands in the South China Sea and the adjacent waters.

Vietnam, Indonesia, and the Philippines subsequently objected to China’s 2009 notes and appealed to the rule of international law and arbitration.

Since China has not clarified through legislation, proclamation, or other official statements the legal basis for the map, the Limits in the Seas study considered three possible interpretations--namely that the dashes represent a claim to islands, a national boundary or historical waters.

To be consistent with the law of the sea, China’s maritime claims to any islands would have to meet the terms set forth in the UN Convention on the Law of the Sea (UNCLOS), namely a territorial sea, a contiguous zone, an Exclusive Economic Zone (EEZ), or a continental shelf.

Because sovereignty over many of the islands featured in China's map are disputed, the maritime zones associated with them also falls into dispute. UNCLOS requires all maritime boundary lines to be negotiated with neighboring States.

As to the second interpretation, if the dashes on Chinese maps are intended to indicate national boundary lines, then those lines would not have a proper legal basis under the law of the sea.

UNCLOS likewise mandates that maritime boundaries be created through agreements between neighboring States; one country may not unilaterally establish a maritime boundary.

Moreover, China's "dashes" fall beyond the 200 nautical miles of any Chinese-claimed land feature.

As to the third interpretation, by which the dashes represent “historic waters” or “historic rights” to waters, such claims fall outside the narrow category for such claims established under UNCLOS.

In addition, the dashed-line claim would fail each element of the convention's test for such claims, according to the report.

The law of the sea does not permit historical claims to override geographic features, the report concluded, adding that the convention was designed to bring clarity and uniformity to the maritime disputes between neighboring states.